16120816.ppt

CHAPTER 1
INTRODUCTION TO WIRELESS
COMMUNICATIONS
Reference: Jorge Olenewa, Guide to Wireless Communications, 3rd edition,
ISBN-13: 9781111307318, 2013 © Cengage Learning 2014
Department of Computer Engineering, Faculty of Engineering
Prince of Songkla University, Phuket Campus

Objectives
2
 Describe how wireless communications
technologies are used today
 List various applications of wireless
communications technology
 Outline the advantages and disadvantages of
wireless communications technology
 List several types of wireless technologies and
their purposes
242-306 Mobile and Wireless Computing

History of Wireless Networks
 Progress of transmission:
 fire and smoke used by Indians ==> messenger on
horseback ==> telephone line ==> networks
 Traditional networks (LAN, MAN, WAN) have
provided great convenience:
 in office, hotel room, or home
 But you cannot utilize the service unless you are
physically connected to a LAN or a telephone line.
 ALOHANET by University of Hawaii:
 7 campuses over 4 islands; star-like structure
centered at the Oahu island in 70’s.
3

History of Wireless Networks
 In 80’s, amateur radio hobbyists built TNC
(terminal node controller) to interface “hams”
radio equipment and their computers.
4

 RF spectrum are available because they exist
worldwide
 using frequencies at will would eventually disable
all communication
 Regulatory bodies have been formed to keep
the RF spectrum organized open for fair use
 There are three main regulatory bodies that
govern the RF spectrum: ITU-R, FCC, ETSI
Wireless communication
5

Progress of Wireless
Communication
 In 1985, FCC authorized the use of ISM bands
for Industrial, Scientific, and Medical for
commercial development.
 ISM is very attractive to vendors because NO
obtaining FCC license is required.
 In 90’s, small-size computers started to appear.
 laptop, palmtop, PDA
 Wireless LAN products populate
6

ISM Band defined by ITU-R
7
Frequency range Bandwidth Center frequency Availability
6.765 MHz 6.795 MHz 30 kHz 6.780 MHz
Subject to local
acceptance
13.553 MHz 13.567 MHz 14 kHz 13.560 MHz
26.957 MHz 27.283 MHz 326 kHz 27.120 MHz Worldwide
40.660 MHz 40.700 MHz 40 kHz 40.680 MHz
433.050 MHz 434.790 MHz 1.84 MHz 433.920 MHz
Region 1 only and
subject to local
acceptance
902.000 MHz 928.000 MHz 26 MHz 915.000 MHz
Region 2 only (with
some exceptions)
2.400 GHz 2.500 GHz 100 MHz 2.450 GHz
5.725 GHz 5.875 GHz 150 MHz 5.800 GHz Worldwide
24.000 GHz 24.250 GHz 250 MHz 24.125 GHz
61.000 GHz 61.500 GHz 500 MHz 61.250 GHz
Subject to local
acceptance
122.000 GHz 123.000 GHz 1 GHz 122.500 GHz
244.000 GHz 246.000 GHz 2 GHz 245.000 GHz

How Wireless Technology is Used
8
 Wireless: describes all types of devices and
technologies not connected by a wire
 Wireless communications: transmission of digital
data without the use of wires
 Various forms of wireless data communications:
 Bluetooth
 WirelessHD
 WiGig
 Satellite
 Cellular
 Wi-Fi-based wireless LANs
 Fixed broadband wireless communications

A Wireless World
9
 Wireless devices
 Distance: up to 330 feet (100 meters)
 Bandwidth: up to 300 Mbps
 Can also include Voice over IP (VoIP)
 Wireless network interface card (Wireless NIC)
 Sends and receives data over radio waves
 Smartphone: Combination mobile phone and
personal digital assistant (PDA)
 Radio frequency identification (RFID) tags: small
chips containing radio transponders

10
Figure 1-1 Home wireless network (WLAN)

Bluetooth and Other Short-Range
Wireless Technologies
11
 Bluetooth
 Wireless standard designed for very short ranges
 Typically a few inches to 33 feet (10 meters)
 Main purpose is to eliminate cables between devices
 Bluetooth communicates using small, low-power
transceivers called radio modules
 Link manager
 Special software that helps identify other Bluetooth
devices, create a link between them, and send and
receive digital data

12
Figure 1-2 Two examples of Bluetooth headsets: mono (left) and stereo (right)

Bluetooth and Other Short-Range
Wireless Technologies
13
 Wireless HD and WiGig
 Can transfer video and sound at speeds between 7
Gbps and 10 Gbps using Ultra Wide Band (UWB)
 Distance: up to 10 meters (only in a room with few or
no obstacles)
 Greater the distance, the slower the transmission
 Piconet
 Wireless personal area network (WPAN)
 Consists of two or more Bluetooth devices that are
exchanging data with each other
 Up seven devices can belong to a single WPAN

14
Figure 1-3 Bluetooth network (piconet) or WPAN between
a cordless handset and a headset

Satellite Networks
15
 Used to transmit data over very long distance
 Repeater
 Located in the satellite itself
 “Repeats” the same signal to another location
down on the surface
 Used to transmit data from one earth station to
another
 Transmission time can be up to 250 milliseconds

16
Figure 1-5 Satellite repeating a signal to another Earth station

Cellular Networks
17
 Modern cellular telephone network
 Built around the concept of low-power transmitters
 With each “cell” handling a number of users
 Transmission towers are spread throughout a
geographical area
 The same radio frequency channels can be reused
by another tower
 Located a few miles away to avoid interference
 Maximizes the use of a limited range of frequency
channels

18
Figure 1-6 Smartphones - Blackberry Bold (left) and Apple iPhone (right)

Cellular Networks
19
 4G (fourth generation) technology
 Uses 100% digital transmission for both voice and
data
 Transmission speed
 Over 150 Mbps when stationary
 45 Mbps for slow-moving pedestrians
 20 Mbps in a fast moving vehicle
 3G (third generation) technology
 Has a theoretical maximum data transmission rate
of up to 21 Mbps
 Realistic speeds are between 3 to 11 Mbps

20
Figure 1-7 Digital cellular network

Wireless Local Area Networks
21
 Wireless Local Area Network (WLAN)
 Extension of a wired LAN
 Connecting to it through a device called a wireless
access point
 Access point (AP or wireless AP)
 Relays data signals among all of the devices on the
wired network
 Each computer on the WLAN has a wireless
network interface card (NIC)
 Has an antenna built into it

22
Figure 1-8 Clockwise from top left: a) access point with built-in antennas,
b) USB Wireless NIC, c) PCMCIA, and d) PCI Wireless NICs

Wireless Local Area Networks
23
 Institute of Electrical and Electronic Engineers
(IEEE) standards
 Established a series WLAN standards
 Most recent IEEE 802.11n-2009 (more commonly
known as IEEE 802.11n)
 Provides for transmission speeds of up to 600 Mbps and
covers distances up to 375 feet

24
Figure 1-10 Office WLAN

Fixed Broadband Wire
25
 Integrated Services Digital Networks (ISDN)
 Transmits at up to 256 Kbps over regular phone lines
 T1 lines
 Transmit at 1.544 Mbps
 Very costly option
 Cable modems
 Generally only available in residential areas
 Digital subscriber lines (DSL)
 Use either regular or special telephone lines
 Speed is dependent on distance between FPE’s main
office and nearest telephone switching office

Fixed Broadband Wireless
26
 Wireless metropolitan area network (WMAN)
 Covers a distance of up to 25 miles
 Based on the IEEE 802.16 WIMAX Fixed
Broadband Wireless standard
 Uses radio waves and small custom antennas on
the roof of each building in WMAN
 Transmission speeds
 75 Mbps at distances of up to 4 miles (6.4 km)
 17 to 50 Mbps at distances over 6 miles (10 km)
 Newer versions of IEEE 802.16m standard will be
able to achieve average speeds up to 100 Mbps

27
Figure 1-11 IEEE 802.16 wireless metropolitan area network (WMAN)

 Free-space optical
communication (FSO) is an
optical communication
technology.
 FSO uses light propagating
in free space to transmit data
for telecommunications or
computer networking.
 The technology is useful
where the physical
connections are impractical
due to high costs or other
considerations.
Fixed Broadband Wireless
28
Photograph courtesy of MRV Communications

The Wireless Landscape
29
 Wireless communications
 Has become a standard means of communication
for people in many occupations and circumstances
Figure 1-14 Wireless communications

30
Table 1-1 Wireless data communications technologies

31
Figure 1-15 Comparing wireless communications technologies

The Wireless Landscape
32
 Speeds of wireless networks vary greatly
depending on:
 Number of users connected
 Amount of data traffic
 Amount of interference present at the time
 Other factors that will be discussed in later chapters
 Job market will increase for:
 Wireless engineers
 Wireless local area network managers
 Wireless technical support personnel

Digital Convergence
33
 Digital convergence
 Refers to the power of digital devices to combine
voice, video, and text-processing capabilities
 As well as to be connected to business and home
networks and to the Internet
 Same concept applies to the development of VoIP
networks
 Use the same protocols and media that once only
carried data
 Wireless technologies are used to fulfill many
daily activities

Wireless Applications
34
 Main areas
 Education
 Home entertainment and Home control systems
 Health Care
 Government and Military
 Office environments
 Event management
 Travel
 Construction and warehouse management
 Environmental research
 Industrial control

Education
35
 Ideal application for colleges and schools
 Instructors can create classroom resources in
their home or school office and easily connect
to campus network in the classroom
 It frees students from having to go to a
specific computer lab or the library
 To get on the school’s computer network
 Wireless technology translates into a cost
savings for colleges
 Traditional classrooms become computer labs
without the expense of additional wiring

Home Entertainment
36
 Wireless communication
 Enables people to download, distribute, and
control all forms of digital entertainment from
anywhere in the house
 Examples:
 Wireless speakers, media players, game consoles,
DVD players, televisions, digital video recorders
(DVRs), and multimedia personal computers

Home Control Systems
37
 Manufacturers are creating wireless systems
that enable us to:
 Control lights, heating, ventilation, air
conditioning, drapes, alarms, door locks, and
home appliances
 Can control from locations throughout the house
or even from smartphones or tablets outside the
home
 Several systems use the ZigBee Alliance
communications protocols and the IEEE
802.15.4 standard

Health Care
38
 Administering correct medication in a hospital setting
 A major concern for the health care industry
 Wireless point-of-care computer systems
 Allow medical staff to access and update patient records
immediately
 Many hospitals use portable devices with barcode
scanners or RFID and a wireless connection
 Patients may have a barcoded or RFID-enabled armband
that can be scanned to access records
 System immediately verifies correct medication

Government
39
 Wireless communication
 Lets residents, city employees, contractors, and utility
staff collect and transmit data to central databases
 Examples:
 Building inspectors can update permit data while at the
construction site
 City employees can locate and monitor municipal vehicles
 Delivers broadband connectivity to schools, libraries, and
government buildings
 Provides free Internet access to residents and attracts
visitors and businesspeople

Military
40
 Latest devices allow military personnel in the
field to:
 Use voice and the Internet
 Receive and transmit full-motion video
 Maneuver remote control survey drones
 Use digital battlefield maps
 Many other applications

Office Environments
41
 Employees in all lines of work no longer have to
be away from the data they need
 To help them make decisions
 Wireless technologies allow businesses to
create an office where the traditional
infrastructure doesn’t exist
 During office renovations or reorganization
 Employees can move to another location and be
connected immediately

Event Management
42
 Wireless networks
 Help identify a stolen or counterfeit ticket
 Can also give a real-time look at traffic flow
 Use to determine where staff might be needed
 In-progress game statistics are available to any fan
in the stadium with a wireless device

Travel
43
 Wireless global positioning systems (GPS)
 Tie into emergency roadside assistance services
 OnStar roadside assistance is an example
 Satellite radio
 Transmits over 150 music and talk stations
 Airport terminals are offering wireless
technologies to passengers
 Airplanes themselves are being equipped with
wireless data access
 City transit systems are also “going wireless”

Construction
44
 Wireless communications
 Send information from the job site to the main office
 Tardy subcontractor or problems with materials
 Alert when maintenance operations need to be
performed on equipment
 Bulldozers and earth graders are being turned into
“smart” equipment
 Exact location of dig coordinates can be transmitted to a
terminal on the bulldozer
 Track engine hours and equipment location

Warehouse Management
45
 Implementing wireless technology is key for
many warehouse operations
 Warehouse management system (WMS)
software
 Used to manage all of the activities from receiving
through shipping
 In the near future
 Most of the bar code functions, including inventory
counting, will be replaced by RFID tags
 Will eliminate the need for printing and affixing labels

Environmental Research
46
 Scientists are now using small, battery- or
solar-cell-powered WLAN sensors
 In places that were previously difficult to access
and monitor
 Considered a major breakthrough in many
scientific fields
 Has helped collect data that used to be very difficult or
impossible to collect and record

Industrial Control
47
 Motes
 Remote sensors
 Can connect to a WLAN
 Then collect data and transmit it to a central location
 Manufacturing managers can monitor equipment
from an office
 Problems can be detected instantly
 Technicians in a control room can monitor status
of every machine or device
 Dispatch a technician when necessary

Wireless Advantages and Disadvantages
48
 As with any new technology, wireless
communications offers both advantages and
disadvantages

Advantages of Wireless
Networking
49
 Mobility
 Freedom to move about without being tethered by wires
 Permits many industries to shift toward an increasingly
mobile workforce
 Creating “flatter” organizations with fewer management
levels between top executives and regular employees
 Easier and less expensive installation
 Installing network cabling in older buildings can be a
difficult, slow, and costly task
 Makes it easier for any office to be modified with new
cubicles or furniture

Advantages of Wireless
Networking
50
 Increased reliability
 Network cable failures may be the most common
source of network problems
 Disaster recovery
 In the event of a disaster, managers can quickly
relocate the office
 Some planners keep laptop computers with wireless
NICs and access points in reserve
 Future Applications
 Every day, a new application for wireless data
transmission is thought of or implemented

Disadvantages of Wireless Networking
51
 Radio signal interference
 The potential for two signals to interfere exists
 Solution: locate source of interference and eliminate it
 Security
 It is possible for an intruder to be lurking outdoors with a
notebook computer and wireless NIC
 With the intent of intercepting the signals from a nearby
wireless network
 Some wireless technologies can provide added levels of
security
 Network managers can limit access

Disadvantages of Wireless Networking
52
 Health risks
 High levels of RF can produce biological damage
through heating effects
 Wireless devices emit low levels of RF while being used
 No clear picture of the biological effects of this type of
radiation has been found to date
 Science today does not yet permit anyone to draw a
definitive conclusion on the safety of wireless
mobile devices
 Be aware of the possibility and monitor ongoing scientific
research

Summary
53
 Wireless communications have become
commonplace
 Wireless networks and devices are found in all
circles of life today
 Wireless wide area networks will enable
companies of all sizes to interconnect their offices
 Without the high cost charged by telephone carriers for
their landline connections
 WLAN applications are found in a wide variety of
industries and organizations

Summary
54
 Remote sensors capable of communicating
using wireless technologies
 Used in large manufacturing facilities to monitor
equipment and for scientific research
 Wireless communication advantages
 Mobility
 Easier and less expensive installation
 Increased network reliability
 Support for disaster recovery

Summary
55
 Wireless communication disadvantages
 Radio signal interference
 Security issues
 Health risks

 Describe all wireless technologies
that you are using in more
details?
 Technology specification
 How do you use them
Homework
56

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